At least 50 million adult Americans have hypertension, an important modifiable risk factor for coronary heart disease, stroke and end-stage renal disease. Efficacious blood pressure lowering medications are available but low adherence to medication by older adults can lead to poor outcomes.The overall objective of the proposed prospective cohort study is to determine factors that are associated with reduced antihypertensive medication adherence among older adults (>=65 years). The factors to be investigated include psychosocial, behavioral, quality of life (QOL), health care system issues including copayment/benefit, knowledge, sexual function (SF), medication class, use of unconventional therapies/lifestyle modifications.and clinical factors. The impact of these factors will be assessed overall and by gender and race. We propose to conduct a prospective cohort study with 2,000 participants >= 65 years of age with diagnosed essential hypertension (HTN) in a managed care organization (MCO). This study is designed to have 80% statistical power to detect relative risks of less than 1.5 of medication adherence at baseline and less than 2.0 for transitioning from high to medium or medium to low adherence over 2 years of follow-up associated with demographic, behavioral, clinical and treatment factors. A random, race-and gender- stratified sample of HTN patients >=65 years enrolled in the Medicare Risk Product of a large southern MCO will be selected from all eligible participants. Patients will be followed prospectively for an average of 2 years and medication adherence, QOL , SF, demographic, treatment, socio-economic, knowledge, clinical and behavioral factors will be determined at baseline and during annual telephone-administered follow-up surveys. Chart abstraction at baseline and follow-up will be used to assess blood pressure control, cardiovascular outcomes and HTN severity. MCO computerized medical record system will be used toaccess data on HTN medications, cardiovascular outcomes, copayment/benefit and utilization. The primary outcome will be medication adherence at baseline and changes in medication adherence during follow-up. In addition, the impact of medication adherence at baseline on blood pressure control, QOL, utilization, and cardiovascular outcomes during follow-up will be examined. Results of this study will lay the groundwork for interventions to improve medication adherence and clinical outcomes in older adults with hypertension and will increase our understanding of factors contributing to therapeutic outcomes in the use of medications by these patients.